摘要:

The 1990s can be seen, in many ways, as a transitional decade. THe concept of environmentally sustainable development is becoming accepted as a paradigm for the 21st century, gradually overtaking the concepts of environmental protection and resource management. It will be increasingly unacceptable to view environmental protection as an add‐on or afterthought to economic development activities. The U.N. Conference on Environment and Development, the ‘‘Earth Summit’’ of June 1992, sough to strengthen economic development in ways that reinforce environmental values.Two of the major, inter‐related, issues driving these changes in approach to both environment and development, are climate change as influenced by human‐generated greenhouse gases, and the reduction of losses, human and economic, due to natural environmental hazards. The Second World Climate Conference in late 1990, lead to opening of international negotiation of a global convention on climate change. This convention, signed at the Earth Summit, ensures that energy, forest management and agricultural policies, in all countries, are being closely re‐examined for their environmental effects. The climate negotiations also addressed adaptation to changes in risks of natural hazards, due to changing climate.The International Decade for Natural Disaster Reduction should be viewed in a similar developmental context. It is clear that losses during natural disasters can seriously set back economic development, estecially in poorer countries and regions. In many vulnerable countries, periodic declines in national economic output are highly correlated with occurrences of major disasters due to tropical cyclones, floods, earthquakes or volcanos. It is also evident that by adequate measures for prevention, warning and preparedness, these disaster losses can be substantially reduced. It is, thus, essential that all national development plans incorporate disaster preparedness activities, and that these activities be seen as one major step towards ensuring development that is sustainable. The International Decade for Natural Disaster Reduction provides the framework for international cooperation to achieve this goal.

ISSN:0094-243X    

DOI:10.1063/1.43888

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The growth of the partnership between the scientific community and intergovernmental organizations is outlined. Reference is made to the interactive nature of the relationship between climate and society and to the development of new methodologies of climate impact assessment to take account of this. It is emphasized that the essence of a disaster is the social disruption rather than the geophysical hazard which causes it. The importance of new approaches and new partnerships to solve the twin challenges of climate change and natural disasters is stressed. The conditions for a meaningful dialogue between partners from differing backgrounds is discussed.

ISSN:0094-243X    

DOI:10.1063/1.43900

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Tropical cyclones rank with earthquakes as the major geophysical causes of loss of life and property. It is therefore of practical as well as scientific interest to estimate the changes in tropical cyclone frequency and intensity that might result from short term human‐induced alterations of the climate. In this spirit a simple Carnot cycle model is used to estimate the maximum intensity of tropical cyclones under the somewhat warmer conditions expected to result from increased atmospheric CO2content. Estimates based on August mean conditions over the tropical oceans predicted by a general circulation model with twice the present CO2content yield a 40–50% increase in the destructive potential of hurricanes.

ISSN:0094-243X    

DOI:10.1063/1.43909

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Under current global weather conditions, tropical cyclones occur across specific stretches of the world’s tropical oceans. With climate change, all the factors controlling tropical cyclogenesis may be altered. The twentieth century has already witnessed global warming, punctuated by a warm spell in the 1930s. The response of the atmosphere to these past events in terms of production of tropical cyclones is only imperfectly known. The area second only to the western North Pacific in frequency of tropical cyclones is the eastern North Pacific. The climatology of tropical storm activity for this region for the period since 1900 is being assembled in hopes that it may provide insight into the role of global warming in tropical cyclogenesis, not only earlier this century but into the next.

ISSN:0094-243X    

DOI:10.1063/1.43886

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

One potential effect of global warming is a change in sea level. This paper outlines the current state of scientific knowledge concerning the response of sea level to global warming.

ISSN:0094-243X    

DOI:10.1063/1.43887

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Rising sea level will increase surface runoff and decrease groundwater discharge from low‐lying coastal areas by raising the water table and thus saturating the soil. As a result, there will be increased upland flooding by freshwater and changes in the productive intertidal and near‐shore ecosystems that depend on the lowered salinities and nutrients provided by groundwater discharge. This paper compares these effects of future increases in sea level with the present variation in runoff and groundwater discharge caused by interannual variations in precipitation and evaporation. The analysis relies on a water balance model calibrated using data from a small watershed on Cape Cod (USA). Interannual variation of runoff and groundwater discharge is estimated by driving the model with 40 years of historical weather data. The results indicate that a 20 cm rise in sea level will double the mean surface runoff and reduce groundwater discharge by half. These conditions are significantly different than the present mean hydrologic conditions. The variability of surface runoff also increases with rising sea level.

ISSN:0094-243X    

DOI:10.1063/1.43889

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Climatic warming during the last 100–150 years has resulted in a significant glacier ice loss from mountainous regions of the world. Most glaciers have undergone thinning and their margins have retreated significantly since the Little Ice Age. Natural processes associated with this loss of glacier ice pose hazards to people and the economic infrastructure in mountain areas. These processes include glacier avalanches, landslides and slope instability caused by debuttressing, catastrophic outburst floods from moraine‐dammed lakes, and outburst floods from glacier‐dammed lakes (jo¨kulhlaups). The total loss of life from glacier‐related catastrophic events in the Andes, Himalayas, Alps, and other major mountain systems is in excess of 30,000; damage to the economic infrastructure of the affected regions is probably in excess of one billion dollars. In 1941, for example a single outburst from a moraine‐dammed lake in the Cordillera Blanca of Peru killed over 6000 people.

ISSN:0094-243X    

DOI:10.1063/1.43890

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

In the late 1970s global temperature rose abruptly, and between 1977 and 1990 has averaged 0.4 °C above the 1940–76 mean. In 1980, 50% of the the alpine glaciers observed in the Swiss Alps, Peruvian Andes, Norwegian Coast Range, Northern Caucasus and Washington’s North Cascades were advancing. By 1990 in response to the warming only 15% were still advancing. During the peak non‐glacier snow melt period glaciers are unsaturated aquifers soaking up and holding meltwater for the first two‐six weeks of the melt season. This storage acts as a buffer for spring snow melt flooding, and spreads the peak spring flow over a longer period. In the late summer glaciers buffer low flow periods by providing large volumes of meltwater. As glaciers retreat the amount of water they can store decreases raising spring flood danger and the areal extend exposed for late summer meltwater generation decreases, thus reducing late summer flow.

ISSN:0094-243X    

DOI:10.1063/1.43891

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Future climate change could have significant repercussions on two related natural hazards: lightning and forest fires. The Goddard Institute for Space Studies (GISS) general circulation model (GCM), has been used to study possible changes in lightning and forest fires as a result of climate change. Initial model results show that for an atmosphere containing twice today’s CO2concentration, the global lightning activity increases by approximately 32%, while the likelihood of severe drought conditions increases from 1% in today’s climate to nearly 50% by the year 2060. Conditions favorable for forest fires are strongly linked to climate, and particularly to drought frequencies. Therefore, increases in both lightning activity and the frequency of droughts could result in dramatic changes in forest fire frequencies and intensities in the future.

ISSN:0094-243X    

DOI:10.1063/1.43892

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Local observations in the tropics show that lightning activity increases strongly with the wet bulb potential, &thgr;w, of boundary layer air. The surface wet bulb temperature controls the vigor of convection and the accumulation of ice phase condensate in the mixed phase region of tropical convection, the apparent seat of lightning activity. The Schumann resonance is a global electromagnetic phenomenon driven by global lightning activity. The Schumann resonance amplitude is shown to follow the fluctuations in mean temperature for the entire tropical belt with a sensitivity consistent with the local observations. The manifestation of the ENSO (El Nin˜o–Southern Oscillation) signal in the Schumann amplitude at a single location is consistent with a synchronous warming and cooling over the entire tropical belt.

ISSN:0094-243X    

DOI:10.1063/1.43893

出版商:AIP    

年代:1992

数据来源: AIP